The present invention relates to plumbing fixtures, and more particularly to the drain at the base of a shower enclosure.
Bathroom plumbing fixtures such as bath tubs, spas, whirlpools, shower stalls, shower surrounds, free standing partial or full shower enclosures, etc., are well known. Such fixtures can be installed in combination or as separate and discrete fixtures. In the case of stand alone shower enclosures, the upright walls that surround the enclosure are typically mounted onto to a generally flat base, sometimes referred to in the industry as a shower or base “receptor”. U.S. Pat. No. 3,457,568 provides an example of a prior art base receptor.
In addition to supporting the enclosure walls, the shower base receptor is also the floor of the enclosure on which a person stands during a shower. As such, the floor surface needs to be capable of bearing loads as well as flat and free of uneven surfaces that would be difficult or uncomfortable to stand on. At the same, the base receptor must have a drain to evacuate the water from the shower.
Many conventional base receptors provide for a recessed drain opening that is only covered by a small grate having openings for the water to pass through. The grate is recessed as well to be generally flush with the floor. However, the openings in the grate must be left unblocked and otherwise make it uncomfortable to stand on with bare feet, and therefore, the usable floor space in the enclosure is effectively reduced by the area of the grate where a person in the shower would avoid standing.
One approach to overcoming this problem is disclosed in U.S. Pat. No. 5,458,769. This patent describes a floor drain that can be used in a shower environment, albeit not specifically disclosed as for a base receptor, in which the drain opening is covered by a “bell” that can be mounted within the drain opening so that its generally flat, smooth top surface is flush (or near flush) with the surrounding floor. Fluid drains into the drain opening through a narrow passage extending around the periphery of the bell. The bell provides an improved and enlarged stepping area than conventional grates since one can comfortably stand on the smooth top surface of the bell without blocking drain flow through the narrow peripheral passage.
However, this type of covered drain typically significantly reduces the effective passage area through which water can drain, thereby reducing flow rate and possible causing flow back-up and standing water in the base receptor. Standing in drain water is unpleasant, and the raised water can slip over the short rim of the receptor base.
The slow drain problem is exacerbated when the water passing through the drain forms a vortex caused by the coriolis effect arising from suction through the drain. The vortex generates a whirlpool-like swirling action in the water as it passes down through the drain. The swirling action of the water passing through the drain can cause water that would otherwise be at the center of the drain to move outwardly toward the drain walls. The unoccupied space in the center of the drain thus effectively diminishes the passage area of the drain, and in further slows the flow rate.
Anti-vortex drains have been developed to break the vortex and allow water to pass through the full area of the drain. These anti-vortex drains are known in the swimming pool industry, and are used to address problems with debris clogging the drain and/or circulatory pumping system of the pool. They have also be developed to address safety concerns caused by the force of the suction of the circulatory system pulling body parts, particularly that of small children, toward or into the drain.
U.S. Pat. No. 5,341,523 discloses one prior art anti-vortex drain for a swimming pool application. The disclosed drain breaks up the vortex at the drain by using a large, flat circular cover flush-mounted within the drain opening. Water drains around the circular periphery of the cover in a more steady manner with less swirling action. The disclosed drain provides for adjustment of the opening size of the peripheral passage to allow for slight flow rate adjustment.
The disclosed drain would be too large and cumbersome for use in a shower receptor. Moreover, like other conventional covered drains, the reduction in drain passage area caused by use of the cover would slow the flow rate through the drain excessively in gravity feed drainage systems, such as shower applications, such that water would likely accumulate around the drain. Thus, the drain disclosed in the '423 patent, even though it is able to reduce or eliminate the vortexes and allow for passage area adjustment, would likely be suitable only for large volume applications, such as pools, which have forced flow circulatory systems and do not need to prevent water from accumulating around the drain.
Hence, a need exists to provide a shower base receptor with a covered drain system that has enhanced flow characteristics.